Fix NPE in onDestroy

 Bug: 3478016

Change-Id: I0bf1819ab786a8b07575856b8cfa4d20bc074e49
diff --git a/src/com/android/browser/Controller.java b/src/com/android/browser/Controller.java
index 062814b..0961f80 100644
--- a/src/com/android/browser/Controller.java
+++ b/src/com/android/browser/Controller.java
@@ -678,7 +678,7 @@
     }
 
     void onDestroy() {
-        if (!mUploadHandler.handled()) {
+        if (mUploadHandler != null && !mUploadHandler.handled()) {
             mUploadHandler.onResult(Activity.RESULT_CANCELED, null);
             mUploadHandler = null;
         }